Various types of ion implantation devices, which accelerate ions from an ion source to desired energy and implant the energy into surfaces of substrates such as semiconductor wafers, are put into practical use (see Patent Document 1).
One example of conventional ion implantation device is explained below with reference to FIG. 11.
FIG. 11 is a plan view illustrating a schematic configuration of the conventional ion implantation device.
A main configuration of the ion implantation device 100 includes, as shown in FIG. 11, an ion source 110, a mass separator 120, a mass separating slit 130, an accelerating tube 140, a quadrupole lens 150, a scanner 160, and a parallelizing device 170.
The reference numeral 180 in the drawing denotes a substrate to be a target into which ions arranged in an end station, not shown, are implanted.
Further, the reference character B denotes ions, but they are occasionally called “ion beam” or “beam”.
The ion source 110 is a device which rips off electrons from atoms and molecules so as to create ions. The mass separator 120 is a device which generates a magnetic field or an electric field, or both of them utilizing a property such that charge molecules such as ions and electrons are deflected in the magnetic field or the electric field so as to specify ion species to be desirably implanted into the substrate 180.
The accelerating tube 140 is a device which accelerates or decelerates desired ion species passing through the mass separating slit 130, but as shown in FIG. 11, normally a plurality of electrode pairs are arranged with uniform intervals axisymmetrically, a high voltage which is equal to the electrode paris is applied so that the ion beam B is accelerated or decelerated so as to be desired implantation energy by the function of an electrostatic field.
The scanner 160 generates an external electric field which is uniform in a direction orthogonal to an advancing direction of the ion beam B, changes polarity and strength of the electric field so as to control a deflection angle of the ions, and as shown in FIG. 11, scans a desired position on the implantation surface of the substrate 180 with the ions B so as to implant the ions B uniformly.
For simplification, FIG. 11 illustrates one electrode pair of the scanner 160 for deflecting the ion beam B to a horizontal direction, but the scanner 160 may deflect it to a vertical direction.
The parallelizing device 170 is an electric magnet which utilizes the property such that the ions B as charge molecules are deflected in the magnetic field so as to suppress diffusion of the beam according to a difference in paths of the respective ions composing the ion beam B and allow the beam B to enter the substrate 180 parallel.
Not shown, but a chamber which is maintained in high vacuum is disposed from the ion source 110 to the substrate 180, and the ion beam B advances through the chamber from the ion source 110 to the substrate 180.
In the above configuration, a basic operation of the conventional ion implantation device 100 is explained below with reference to FIG. 11.
In the conventional ion implantation device 100, since the predetermined ion species are implanted into the entire implantation surface of the substrate 180 for the ions B at uniform density by predetermined energy, for example, the ion beam B which is drawn out from the ion source 110 by energy of about 30 keV is deflected by the mass separator 120, and only predetermined ion species are sorted out by the mass separating slit 130.
The sorted-out ion beam B is accelerated or decelerated into energy of about 10 to 500 keV by the accelerating tube 140, and an external electric field with cycle of about 1 kHz, for example, is applied by the electrostatic type scanner 160 having two electrode pairs which carries out scan with the ion beam B to the horizontal or vertical direction, so that the scanning surface of the substrate 180 is scanned.
The above case picks up the electrostatic type scanner 160 which carried out the scanning with the ion beam B using the external electric field, but instead of the electrostatic type scanner 160, a magnetic type scanner is occasionally used.
As shown in FIG. 11, it is often the case that an adjusting device such as a quadrupole lens 150 is provided between the accelerating tube 140 and the scanner 160 in order to adjust a beam spot shape of the ion beam B on the substrate 180.
Since a depth that the ions B enter a solid can be accurately controlled by the energy of the ions B, for example, when a distribution of the dose amount of the ion beam B is monitored at the time of starting up the ion implantation device 100, the desired ion species can be subject to uniform ion implantation process by scanning the scanning surface of the substrate 180 with the ion beam B.
The ion beam scanning mechanism of a second conventional ion implantation device is explained below simply.
The scanning mechanism of the second conventional ion implantation device is shown in FIG. 3 of Patent Document 2, but a scanning electric magnet having a laminated structure is provided in order to avoid a reduce in the magnetic field due to an eddy current, and an exciting current which is allowed to flow in the scanning electric magnet is modulated at a high speed of about 500 Hz, so that the scanning with ion beam is carried out.
The ion beam scanning mechanism of a third conventional ion implantation device is explained below simply.
The scanning mechanism of the third conventional ion implantation device is shown in FIG. 1 of Patent Document 3, but a deflecting electric magnet for deflecting an ion beam in a predetermined plane with respect to a standard axis as a center trajectory is provided onto a beam line, a deflection chamber portion provided with the deflecting electric magnet in the chamber through which the ion beam passes is electrically independent, and an electric potential of the deflection chamber is modulated so that the scanning with the ion beam is carried out.    Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 8-213339    Patent Document 2: JP-A No. 4-253149    Patent Document 3: JP-A No. 53-102677    Non-Patent Document 1: S. Ogata et al. Proceedings of Int. Conf. on Ion Implantation Technology, IEEEE 98 EX144 (1999) 403